A lack of breathing air and a need for floatation are often combined in a same catastrophic event. For example, people trapped inside a submerged vehicle need breathing air to get out of the vehicle and added buoyancy to swim to the shore. Similarly, smoke inhalation and drowning are often combined risks in an air plane crash or in the case of a burning ship. Home owners living near flood plains could also be exposed to smoke inhalation from a house fire due to electrical short circuits caused by rising water, and drowning when evacuating their house during an inundation; Therefore it is believed that a need exists for a lifesaving device offering both floatation and oxygen supply for at least a short period of time.
Conventional lifesaving devices for use in homes, vehicles, cottages and small crafts are generally limited to containers of breathable gas, gas filters, floatation vests and inflatable rafts. Both a breathing aid and floatation equipment are purchased, stored and maintained separately and therefore, people often neglect to obtain one or the other or both.
Examples of emergency oxygen or air supply devices of the prior art are described in the following documents. These documents are divided in two groups. The documents in the first group pertain to devices used to filter ambient air delivered to a mouthpiece, and the documents in the second group pertain to devices incorporating a limited supply of breathable gas contained under pressure in a small cylinder. Examples of the devices of the prior art having a filter incorporated therein are as follows:    U.S. Pat. No. 4,515,156 issued to N. M. Khudosovtsev et al. on May 7, 1985;    U.S. Pat. No. 6,032,668 issued to C. Y. Chung on Mar. 7, 2000;    CA Patent 2,084,765 issued to L. J. Swann on Nov. 12, 1996.
Examples of breathing devices having a supply of respirable gas included therein are as follows:    U.S. Pat. No. 2,831,607 issued to A. J. Berndt on Apr. 22, 1958;    U.S. Pat. No. 4,440,163 issued to G. Spergel on Apr. 3, 1984;    U.S. Pat. No. 5,979,442 issued to R. J. Orr on Nov. 9, 1999;    U.S. Pat. No. 6,412,482 issued to C. D. Rowe on Jul. 2, 2002;
Both the filter and the pressurized cylinder types of breathing devices are advantageous to prevent inhalation of smoke or toxic gases for example for a period of time which is sufficiently long to allow a person to get away from a danger area. In the case of the CA Patent 2084,765 for example, a supply of breathable air for a period of 10 minutes is suggested. In another example, the U.S. Pat. No. 4,440,163 suggests a supply of respirable air for a period of about 5 minutes.
In regard to prior art in the field of inflatable lifesaving devices, the following documents represent good examples of floatation equipment that are inflatable by mouth of the user:    U.S. Pat. No. 2,742,654 issued to V. H. Hurt on Apr. 24, 1956;    U.S. Pat. No. 5,516,233 issued to W. L. Courtney on May 14, 1996;    U.S. Pat. No. 4,813,899 issued to H. Fujimoto on Mar. 21, 1989.
Although the above inflatable devices have a mouthpiece connected to one or more inflatable bags, each mouthpiece is equipped with a check valve that prevents re-breathing from the bags. These devices are therefore not appropriate for preserving someone's life in a hazardous situation requiring both floatation and respirable air.
More relevant prior art devices preceding the present invention consist of floatation vests, each being made of two compartments from which at least one contains respirable air and is equipped with a hose and a mouthpiece for inhaling the air from the bag. These floatation vests are described in the following documents:    U.S. Pat. No. 3,866,253 issued to A. J. Sinks et al. on Feb. 18, 1975;    U.S. Pat. No. 3,877,425 issued to W. J. O'Neill on Apr. 15, 1975;    U.S. Pat. No. 4,324,234 issued to S. G. Maness on Apr. 13, 1982.
In the case of U.S. Pat. No. 3,866,253, a diver wearing the vest can inflate one of the compartments by mouth, and where necessary, re-breathe the air from this compartment. The other compartment is inflated by a cartridge of compressed CO2 gas. The U.S. Pat. No. 4,324,234 suggests a dual-chamber vest wherein one of the chambers is filled with compressed air or breathable gas and the other is filled with CO2 gas. The document suggests an amount of air sufficient to re-breathe from the bag for a period of 3 to 5 minutes to escape from a danger situation.
One of the problems associated with a pressurized gas container used in a breathing device is that the discharge of the container into the bag of the device increases the pressure of the breathable gas inside the bag or vest and makes in difficult, at least initially, to control the flow of gas through a mouthpiece. The pressure surge of the discharging cylinder is susceptible of causing a wearer to inadvertently over-breathe or otherwise let escape a substantial amount of gas through the mouthpiece, and to waste a portion of the lifesaving feature of the device. Therefore conventional breathing apparatus using pressurized cylinders have pressure regulators incorporated therein or calibrated orifices to limit the flow of gas to the mouthpiece.
However, a pressure regulator mounted in a lifesaving breathing device increases the manufacturing cost of the device and is believed to be a determining factor limiting the accessibility of the device to a large number of people. Similarly, the use of an orifice in a breathing device limits the amount of air available to the user at any given time. As the pressure drops in the supply cylinder, the flow of gas also drops across the orifice and to the mouthpiece. This reduction of flow to the mouthpiece could induce a sense of panic to the user.
On the other hand, when the respirable gas is expanded in a bag at atmospheric pressure, it is estimated that a volume of gas of about 660 cubic inches is required for each minute of breathing time. A bag containing 3 to 5 minutes worth of breathable gas can be seen as a serious encumbrance to get out of a cramped space in a danger situation.
As such, it may be appreciated that there continues to be a need for a new and improved lifesaving floatation and breathing device having a reasonable volume of breathable air therein and which operates without a pressure regulator or an orifice.